Singapore Clinical Practice Guidelines For Sarcopenia: Screening, Diagnosis, Management and Prevention

OBJECTIVES

To present the local evidence and final recommendations of the Clinical Practice Guidelines workgroup convened by the Chapter of Geriatricians and the Society for Geriatric Medicine Singapore. The aim is to develop contextualized evidence-based recommendations that facilitate adoption of the Asian Working Group for Sarcopenia (AWGS) 2019 consensus into current practice in Singapore.

METHODS

The workgroup drew upon the AWGS'2019 consensus, updated literature review of Singapore studies till 31 Dec 2020, and evidence from recent systematic reviews. From 40 local studies included for data extraction, we constructed evidence tables organized as: definition and epidemiology; diagnosis and evaluation; and treatment and intervention. Twenty recommendations - case-finding, diagnosis, treatment, prevention, research - were developed, and graded for strength and quality using the GRADE approach. Consensus from an expert panel(N=23) was achieved after two rounds of the modified Delphi process.

RESULTS

The local prevalence of sarcopenia among community-dwelling older adults ranged from 13.6% to 25%. Most studies adopted the AWGS'2019 and AWGS'2014 criteria. Reported case finding tools include SARC-F, calf circumference (CC) and SARC-CalF. Gender-specific AWGS cut-offs for appendicular skeletal mass were used to define low muscle mass. Different protocols and dynamometers were used to assess handgrip strength, whilst gait speed and 5-times chair stand were commonly used to assess physical performance.

RECOMMENDATIONS

We conditionally recommend a case-finding approach in at-risk older adults using validated case-finding tools. Screen-positive individuals should be assessed for 'possible sarcopenia' and underlying causes. For diagnosis, we conditionally recommend using the AWGS'2019 algorithm, and dual-energy X-ray absorptiometry when necessary to determine low lean mass for a confirmatory diagnosis of sarcopenia. For treatment, we strongly recommend resistance-based exercises and conditionally recommend a quality protein-rich diet/protein supplementation, with Vitamin D supplementation for insufficiency (<30 micrograms/L). For prevention, we recommend regular resistance-based physical activity and adequate protein intake (≥1.0g/kg bodyweight). We encourage more research to address local evidence gaps.

Follicular Adenomatoid Odontogenic Tumor in Mandible: A Rare Case Report

Adenomatoid odontogenic tumor (AOT) is a relatively rare, benign, hamartomatous, and cystic odontogenic neoplasm that was first described more than a century ago. The lesion still continues to intrigue experts with its varied histomorphology and controversies regarding its development. The present article describes a case of cystic AOT with an unusual histomorphology associated with an impacted 44 in a 21-year-old male.

Le Fort I distraction osteogenesis of the edentulous maxilla

Rehabilitation of the edentulous patient with atrophic ridges is a problem especially when compounded with a severe prognathic inter-arch relationship. It is difficult to rehabilitate these patients prosthetically without correction of the malrelation of the jaws. The established surgical techniques for correcting combined sagittal and vertical discrepancies of edentulous jaws are often prolonged and complex with attendant morbidity. This article presents a novel, simple method of correction of severe interarch sagittal discrepancy (more than 15 mm) by performing distraction osteogenesis at Le Fort I level using an internal maxillary distraction device. This method is a simple, predictable and stable option for the correction of a severe, unfavourable intermaxillary relation in edentulous patients.

Identification of hepatitis B virus core mutants by PCR-RFLP in chronic hepatitis B patients from Punjab, Pakistan

Chronic hepatitis B virus (HBV) infection remains a major health issue worldwide. Several factors including core gene variation are responsible for the development of chronicity of HBV infection. The present study was designed to identify the variations in the core region of the HBV genome in a local population of chronic hepatitis B patients (n = 57) using a PCR-based restriction fragment length polymorphism (PCR-RFLP) method. Fifty subjects were found to be positive for the presence of HBV DNA. For the core region genotyping, the Ava II and Msp I restriction enzymes were used. Mutations at nucleotide (nt) 2147 and nt 2362 in the HBV genome in the core region for Ava II (A4 type, 74%) and nt 2331 for Msp I (M1 type, 66%) were observed as the most common pattern. These results are different from those of previously reported studies on other populations and thus appear to be unique to the Pakistani population. This type of characterization of core mutants may be useful for the design of vaccines based on viral epitopes that are effective for the Pakistani population. Moreover, these unique genotypic patterns for the HBV core gene might be some of the main factors responsible for understanding the underlying mechanism by which HBV chronicity is developed in the Pakistani population.

Skeletal stability after correction of maxillary hypoplasia by the Glasgow extra-oral distraction (GED) device

Maxillary distraction osteogenesis delivers excellent results, particularly in patients with clefts. In the past, devices such as the conventional facemask and the rigid external distraction device have been used to correct maxillary hypoplasia after a Le Fort I osteotomy. We describe a new device, the Glasgow extra-oral distraction device. The extent of skeletal and dental stability of corrections achieved in 10 patients with maxillary hypoplasia associated with clefts was satisfactory. This device costs little, can be produced in developing countries, and provides effective treatment for severe secondary deformity associated with clefts.

Odontogenic myxoma in a child: diagnostic and treatment dilemmas

A rare case of odontogenic myxoma of the mandible in a 10 year old child has been reported and an attempt has been made to critically analyze the case as well as the diagnostic dilemmas related to myxomatous tumours to improve our knowledge and skills in their management.

Anomalous burning rates of flamelets induced by self-similar multiple scale (fractal and spiral) initial fields

In contrast to the classical problem of a single idealized flamelet (which is described by a nonlinear reaction-diffusion equation of motion) which propagates at a constant burning rate, self-similar multiple scale fields, whether fractal or nonfractal, induce anomalous rates of burning determined by the space-filling properties of the initial field. We compare the regimes induced by (line-cuts through) three specific geometries with distinct space-filling characteristics: (1) an algebraic spiral which has capacity (box-counting dimension) D(k)>0, and fractal dimension H=0; (2) an exponential spiral which has D(k)=0 and H=0, and geometric ratio R>1; (3) a fractal Cantor dust which has D(k)=H>0. The (nondimensional) burning rate U(B) induced by all three geometries takes the general form U(B) approximately F(tau(-zeta)), where F is a function whose form depends on the specific geometry, zeta is an exponent that contains the space-filling characteristic of the geometry, and tau is a nondimensional time. (1) For the algebraic spiral, F(x)=1(x), and zeta=D(k); F is continuous. (2) For the exponential spiral, F(x)=ln(x), and zeta=1/(R-1); F is continuous. (3) For the fractal Cantor dust, F(u)(x)=1(x), and zeta=H (for the envelope); F itself is a step-like discontinuous function. Thus, as D(k)-->0, or as H-->0, or as R-->infinity, then zeta-->0 and U(B)-->const; and as D(k)-->1, or as H-->1, (space filling) then zeta-->1; and as R-->1 (space filling) then zeta-->infinity. Two numerical methods, a fundamental (Eulerian) solution to the equation of motion and a Lagrangian model for flamelet propagation, confirm these theoretical predictions. The Lagrangian model is based on the idealized flamelet as a "point" with finite flame thickness Delta(L), (which is determined by the two-flamelet collision process), propagating with a given flame speed U(L). The Lagrangian model allows simulations in parameter ranges not easily accessible by the fundamental method (such as the case for the fractal Cantor dust). Interestingly, the linear regime of scalar diffusion in an algebraic spiral field displays the same dependence on D(k) as in the present reaction-diffusion case. The nonlinear regime of advection-diffusion (Burger turbulence) shows a different dependence on D(k).

Cervical infection due to an unusual displacement of teeth as a result of trauma

An unusual and extremely rare displacement of teeth due to trauma, resulting in cervical space cellulitis with probable secondary complications is presented.

Interactions of troponin subunits: free energy of binary and ternary complexes

We have determined the free energy of formation of the binary complexes formed between skeletal troponin C and troponin T (TnC.TnT) and between troponin T and troponin I (TnT.TnI). This was accomplished by using TnC fluorescently modified at Cys-98 with N-(iodoacetyl)-N'-(5-sulfo-1-naphthyl)ethylenediamine for the first complex and TnI labeled at Cys-133 with the same probe for the other complex. The free energy of the ternary complex formed between troponin C and the binary complex TnT.TnI [TnC.(TnT.TnI)] was also measured by monitoring the emission of 5-(iodoacetamido)eosin attached to Cys-133 of the troponin I in TnT.TnI. The free energies were -9.0 kcal.mol-1 for TnC.TnT, -9.2 kcal.mol-1 for TnT.TnI, and -8.7 kcal.mol-1 for TnC.(TnT.TnI). In the presence of Mg2+ the free energies of TnC.TnT and TnC.(TnT.TnI) were -10.3 and -10.9 kcal.mol-1, respectively; in the presence of Ca2+ the corresponding free energies were -10.6 and -13.5 kcal.mol-1. Mg2+ and Ca2+ had negligible effect on the free energy of TnT.TnI. From these results the free energies of the formation of troponin from the three subunits were found to be -16.8 kcal.mol-1, -18.9 kcal.mol-1, and -21.6 kcal.mol-1 in the presence of EGTA, Mg2+, and Ca2+, respectively. Most of the free energy decrease caused by Ca2+ binding to the Ca2+-specific sites is derived from stabilization of the TnI-TnC linkage.(ABSTRACT TRUNCATED AT 250 WORDS)

Structural and biological studies on synthetic peptide analogues of a low-affinity calcium-binding site of skeletal troponin C

We have synthesized four oligopeptides that are structural analogues of a low-affinity Ca2+-specific binding site (site II) of rabbit skeletal troponin C. One analogue (peptide 3) was a dodecapeptide with a sequence corresponding to the 12-residue Ca2+-binding loop (residues 63-74 in troponin C), two (peptides 4 and 5) were 23-residue in length, corresponding to residues 52-74 of the protein, and the fourth (peptide 6) was a 25-residue peptide corresponding to residues 50-74. All four peptides had one amino acid substitution within the 12-residue binding loop in which phenylalanine at position 10 was replaced by tyrosine to provide a marker for spectroscopic studies. In addition, peptides 3 and 4 each had a second substitution within the binding loop where glycine at position 6 was replaced by alanine. The second substitution was motivated by the conservation of glycine at the position in the Ca2+-binding loops of all four Ca2+-binding sites in troponin C. The peptides were characterized by their intrinsic fluorescence, ability to enhance the emission of bound Tb3+, affinity for Ca2+ and Tb3+, and circular dichroism. The affinity for Ca2+ was in the range 10-10(2) M-1, and the affinity for Tb3+ was in the range 10(4)-10(5) M-1. The binding constants of the longer peptides were several-fold larger than that of the dodecapeptide. With peptides 4 and 5, substitution of glycine by alanine at position 6 within the 12-residue loop decreased the affinity for Ca2+ by a factor of four, but had little effect on the affinity for Tb3+. However, the mean residue ellipticity of peptide 4 was substantially higher than that of peptide 5. Since peptide 4 differs from peptide 5 only in the substitution of glycine at position 6 in the loop segment, the conservation of glycine at that position may serve a role in providing a suitable secondary structure of the binding sites for interaction with troponin I. Peptides 4 and 6, when present in a large excess, mimic troponin C in regulating fully reconstituted actomyosin ATPase by showing partial calcium sensitivity and activation of the ATPase. Since these peptides are the smallest peptides containing the Ca2+-binding loop of site II, their biological activity suggests that a Ca2+-dependent binding site of troponin C for troponin I could be as short as the segment comprising residues 52-62.

Control of intra- and extra-cellular sulphydryl-disulphide balances with gold phosphine drugs: 31P nuclear magnetic resonance studies of human blood

Contrasting reactions of the antiarthritic complexes ClAuPEt3 and ClAu(PEt3)2 with blood have been studied by 31P nmr spectroscopy. The monophosphine complex has two binding sites in erythrocytes, probably at the SH groups of glutathione and haemoglobin. The bis complex solidifies blood via a reductive denaturation of albumin, with the release of OPet3.

A double-blind comparison of fluphenazine decanoate and flupenthixol decanoate in the treatment of acute schizophrenia

A double-blind comparison of fluphenazine decanoate and flupenthixol decanoate in 40 consecutive admissions showed no difference in anti-psychotic effect or extrapyramidal side effects after 56 days. However, the trial identified a different effect of the drugs on mood. Flupenthixol decanoate had an elating effect that was most marked during the week following injection. Fluphenazine decanoate tended to lower mood. The results would suggest that in acute schizophrenia, fluphenazine decanoate would be the more appropriate drug in elated or acutely disturbed patients, but that in patients with a lowered mood or a history of depression, flupenthixol decanoate would be the more appropriate drug. It was emphasised that these mood changes were observed in patients with acute schizophrenia and that extrapolation from these results to maintenance therapy of chronic relapsing schizophrenia should only be made with caution. The results suggest that 40 mg of flupenthixol decanoate is approximately equal to 25 mg of fluphenazine decanoate. Analyses of covariance showed a significant positive correlation between the incidence of extrapyramidal side effects and duration of illness.